Air-cleaner blade



Sept. 24, 1929. H. G. KAMRATH AIR CLEANER BLADE Filed Deo. 29, 1926Patented Sept. 24, 1929 UNITED STATES PATENT OFFICE HERBERT G. KAMRATH,F FLINT, MICHIGAN, ASSIGNOR T0 PANY, OF FLINT, MICHIGAN, A COMPANY 0F AC SPARK PLUG COM- MICHIGAN AIR-CLEANER BLADE Application filed December29, 1926. Serial No. 157,761.

This invention relates to air cleaners and particularly to a blade to beused in cleaners of the centrifugal type.

According to the preferred embodiment of my invention the blade is givena form possessing two important advantages. Thus 1t is shaped to directthe air outwardly as well as in a whirling path so that the air travelsthrough the casing in a thin whirling stream closely hugging the casingwall. This increases the velocity of the air stream and facilitatesseparation of dust. To achieve the outward movement of the air, it hasheretofore been considered necessary to employ special surfaces inaddition to the blades themselves. By eliminating such special surfacesthe construction is much simplified and` lcheapened without loss ofefliciency. The

blade is also shaped so as to rcducerestriction to air flow to aminimum. This is accomplished by offsetting the bod of the bladerearwardly in the direction o air flow, so as to increase the size ofthe passages between adjacent blades.

Obviously if but one of the above advantages is desired, the bladel maybe shaped so as to give the desired characteristic alone.

Referring to the drawing:

Fig. 1 is a longitudinal view of an air cleaner having blades embodyingmy inven# tion, parts being broken away andl parts in -section to betterillustrate the invention.

Fig. 2 is an end view of the cleaner shown in Fig. 1. v

Fig. 3 is a. side view of one of the blades.

Figs. 4, 5, 6 and 7 are sectional views taken on the correspondingsection lines of Fig. 3.

Reference character 2 indicates the casing of my cleaner. In one end ofthe casing is secured annulus 4 in which my improved blades 6 areformed. Within the annulus is secured the clean air discharge'conduit 8`and within the conduit 8 is secured air straightener 10. The rear endof the casing 2 is provided with port 12 for the discharge of dust.

The cleaner illustrated is butl one 'ofmany types of centrifugalcleaners in which my improved blades may be employed.f"`This cleaner isassembled of sheet metal parts for simplicity and economy ofconstruction and while this construction is to be preferred in mostcases, it is to be understood that the design of blade which is thesubject matter of this application may equally well be used in cleanersof machined or cast construction.

In the specific design illustrated the annulus 4 is provided with aninterior flange 14 in which the conduit 8 is seated and to which it issecured and with an external flange 16 secured to the flange 18 on thecasing 2, by crimping. The blades 6 are pressed rearwardly from themetal of the annulus and lare accurately formed so that they direct theair both outwardly'and in a whirling path. Thus the forward edges 2() ofthe blades as clearly illustrated in Figs. l and 3, extend in a radialplane perpendicular to the axis ,of the cleaner. The remaining portions22 of the blades as best illustrated in Fig. 3, slope both rearwardlyand outwardly toward the casing wall.

In the specific design illustrated the main portion of the blades 6 maybe defined as the warped surface produced by a line moving along thelines defined by the forward and rearward edges of the blades andmaintaining at all times a constant angle with the line of the forwardedge as illustrated by the parallel section lines 4 4, 5 5, 6 6 and 7 7.If desired, a sightly curved generatating line may be employed insteadof a straight line. By reference to Figs. 4 to 7, it will be noted thatthe angle which the sections shown in these figures make with the planeof the annulus increases progressively.

It will be noted by reference to the tigures that the blades have buttwo free edges, one numbered 30 extending radially and the othernumbered 32 extending substantially circumferentially. In other words,the inner ends of the blades are in radial continuity with the centralportion of the annulus 4.

It will also be noted that the inner ends of the blades are connectedwithr the central portion'24 of the` annulus`4 by means of a curvedportion 26. Thus, `in'effeot the major portions-'of the blades arebodily oflset'rearwardly of'theannulus. The purpose of this is toincrease the yg'ap between adjacent blades and thereby reduce theobstruction to air flow to a minimum. This bodily offsetting of theblades may be geometrically. defined by noting that, as shown in Figure3, the angle which the free radial edge 30 of the blade 6, whenextended, makes with the plane of the plate is less than the angle whichan imaginary line 34 drawn from the outer end of the free radial edge ofthe blade makes with a point in the plane of the plate and in the linedefining the innermost portion of the plate.

The warping of the blade as described will cause the air entering thecleaner to be direoted in a thin whirling stream hugging the inner wallof the casing. This will much more effectively separate out dustparticles than former types of cleaners in which there was no outwarddeflection of the entering air. Upon reaching the closed end of thecleaner the dust is discharged through port 12, and the air streamreverses its direction passing outwardly through port 8 to thecarburetor or other apparatus to be supplied with air. The straightener10 performs its usual function of assisting in the discharge of the aircolumn. The offsetting of the blades by the use of the curved connectingportion. 26 greatly increases the air gap between adjacent blades andreduces restriction to flow. While the blade possesses these importantadvantages, it costs about the same to make as the blades of the priorart.

It is understood, of course, that the terms forwardly, rearwardly, andthe like, used in the specification and claims of this application areto be construed in a relative sense only for it is obvious that theparts may be reversed without altering their funct'ion.

I claim:

1. An air cleaner comprising a casing having an open end, a plate in theopen end of the casing formed to provide a central portion and aplurality of blades extending radially therefrom, said blades beingshaped to provide substantially radial portions and portions bodilyoffset from the plane of the plate adapted to impart a whirling motionto the entering air, the inner ends of said offset portions beingconnected with the central portion of said plate by sharply curvedcontinuations thereof.

2. In the combination. as defined in claim 1 the offset portions ofsaid/blades being warped to direct the air outwardly as well asrearwardly. y

3. An air cleaner comprising a casing, a blade associated with thecasing'for imparting a whirling motion to the air passing therethrough,said blade having a radial portion-and a portion extending to one sideof the plane in which said radial portion lies, said last :named portionbeing characterized by a sharp curve connecting it to the radial portionadjacent the center of the cleaner and blending into a relatively flatportion extending to the tip of the blade to reduce restriction of flowto a minimum. Y

4. An air cleaner comprising a casing having an open end, a platespanning the open end of the casing formed to provide an annular seriesof blades each extending at an angle to the plane of the plate andarranged to impart a whirling motion to the entering air, said bladesbeing warped to simultaneously throw the air in an outwardly direction,the inner ends of said blades being in radial continuity with saidplate, and said ends being provided with offset bends to increase thegap between adjacent blades and reduce restriction to air flow.

5. In an air cleaner the combination of a cylindrical casing, a platespanning the open end of the casing and formed to provide an annularseries of blades bent out of the plane of the plate to impart a whirlingmotion to the entering air, the air directing surfaces of each of saidblades being in the form of a plane warped to give the air particles agreater component of motion in a radial di.- rection to cause them tofollow the inner wall of the casing in a thin stream.

6. An air cleaner comprising a casing having an air inlet, a clean airoutlet, and an outlet for the discharge of dust separated from the airstream passing through the casing, and a plurality of blades associatedwith said casing for directing the air in a whirling path, each of saidblades having its body portion extending rearwardly in angular relationto the direction of flow of the enter'- ing air to direct the air in awhirling path, the body of said blade likewise sloping outwandly towardthe periphery of the cleaner to simultaneously direct the air in la thinstream along the casing wall, the inner end of the blade extendingsharply forwardly from the rearward edge of the blade to the forwardedge to reduce obstruction to flow.

7 In an air cleaner, a substantially cylin drical easing having one endopen to provide an air inlet, a plate spanning the open end of thecasing out of which are integrally formed an annular series of bladesbent out of the plane of the plate to impart a whirling motion to theentering air, substantially the whole of the free radial edge of each ofthe blades being located in a line which makes a smaller angle with theplane of the plate than a line drawn from the outer end of the said freeradial edge of the blade to a point in to the entering air, substantiallthe whole of a side edge of each of the bla es bein 1ocated on one sideof the plane of the p ate, each of said blades being twisted between 5its ends so that the angle which the generating line of the blade whichextends at substantially right angles to a radius of the blade makeswith the plane of the blade adjacent the axis of the casing is less thanthe angle which the said generating line makes with the said plane atpoints radially outward therefrom.

In testimony whereof I aix my signature.

HERBERT G. KAMRATH. f

